The High Energy Stereoscopic System (H.E.S.S.) is a system of Imaging Atmospheric Cherenkov Telescopes (IACTs) located in the Khomas Highland in Namibia. It measures cosmic gamma rays of very high energies (VHE; >100 GeV) using the Earths atmosphere
as a calorimeter. The H.E.S.S. Array entered Phase II in September 2012 with the inauguration of a fifth telescope that is larger and more complex than the other four. This paper will give an overview of the current H.E.S.S. central data acquisition (DAQ) system with particular emphasis on the upgrades made to integrate the fifth telescope into the array. At first, the various requirements for the central DAQ are discussed then the general design principles employed to fulfil these requirements are described. Finally, the performance, stability and reliability of the H.E.S.S. central DAQ are presented. One of the major accomplishments is that less than 0.8% of observation time has been lost due to central DAQ problems since 2009.
H.E.S.S. is a system of Imaging Atmospheric Cherenkov Telescopes (IACTs) measuring cosmic gamma-rays with very high energies in Namibia. Extending the array with a fifth telescope with a mirror area of 600 m$^2$ leads to a lower energy threshold as w
ell as an increased sensitivity of the system. Moreover, it is now the first IACT array consisting of telescopes with different sizes. Low-energetic gamma-rays detected by the telescopes can either be analyzed monoscopically, allowing for a lower threshold, or stereoscopically, using hybrid events only which leads to a better reconstruction performance. We present the status of the monoscopic analysis of H.E.S.S. II events. In order to cross-check the results, we use two independent analysis chains, based on different reconstruction methods. The first method uses the second moments of the cleaned camera image (Hillas parameters) in order to deduce the properties of the primary particle. The background discrimination of this method can be optimized with multi-variate analysis techniques. The second method is based on the comparison of the camera image with the results of a semi-analytical model of the air shower using a Loglikelihood-Maximization. We present the status of these analysis efforts and their respective performances. One of the chains has been applied on real data of the Crab Nebula. All results shown here have to be considered preliminary.
